A broadcast control channel is typically a downlink channel received from the network infrastructure that contains specific parameters needed by a mobile subscriber in order for the mobile subscriber to identify the network and gain access to it. Often times, the broadcast control channel assists the mobile in translating between a logical and a physical channel, where the broadcast control channel will sometimes include frequency and timing information, that assist in accessing the network infrastructure's other channels.
Because of the importance of the broadcast control channel information in establishing a wireless communication link between the mobile subscriber and the network infrastructure, it is beneficial to organize and arrange the control channel information so as to enhance the reliability of the communication of the broadcast channel information. In at least some instances, the data will be encoded so as to include error detection and error correction information, as well as transmit information redundancies.
In at least some instances, the broadcast control channel information will be organized and arranged to be communicated during transmission intervals, where some of the broadcast control channel information may be communicated multiple times during which at least some of the information will remain the same or static. Each separate transmission within a transmission interval is sometimes embedded within a specific subinterval of the transmission interval referred to as a frame, where all or some of the frames associated with a particular broadcast communication channel, herein referred to as an active frame, may include broadcast control channel information. In some instances, some of the broadcast control channel information may vary between frames.
For example, information such as channel bandwidth, base station, and reference power levels, which may be periodically transmitted via a broadcast control channel may be defined as remaining static and/or invariant for the duration of a transmission interval. Other information such as system frame number, which corresponds to a system time reference may be allowed to vary between frames, even within a transmission interval.
In at least some proposals, the static information may be encoded using various transmission configurations, which define the conditions under which and the nature of a combination of encoding, modulating, interleaving and scrambling is performed, which in at least some instances can serve to further assist in the reliable receipt of the same. Multiple static retransmissions of the encoded data using the same or related transmission configurations can be used to allow for the combining of the received information by the mobile station across multiple transmissions or active frames within a particular transmission interval. However, the incorporation and/or encoding of some information that varies between frames can make the combining of multiple transmissions across multiple active frames of a transmission interval more difficult, as it is not always clear to the receiver how the varying data might affect the format after encoding between active frames during which the broadcast channel information is being transmitted. As a result, information that varies between frames is sometimes excluded from some encodings, which are used to enhance the reliability of the information being communicated.
The applicants have recognized that it is possible to sometimes identify invariant subportions of generally variant information, and include the invariant subportions in the other non-varying data that is being encoded in conjunction with a corresponding transmitter configuration. Furthermore, the size of the variant information can sometimes be minimized by controlling the nature of the variant information relative to a transmission interval boundary, and that the variant information can sometimes be communicated without including the variant information in the data being encoded for transmission. Still further, it is possible to accommodate the combining of some information that is allowed to vary between transmissions, which in turn enables the more reliable receipt of the information.